Folding knife



FIG. 1 is a perspective view of a folding knife, showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a front view thereof; and,

FIG. 7 is a back view thereof.

The broken lines depict portions of the folding knife in which the design is embodied that form no part of the claimed design. 

CLAIM We claim the ornamental design for a folding knife, as shown and described. 